The subject invention provides novel and advantageous methods for growing bacteria. The methods of the subject invention are particularly advantageous for growing parasitic bacteria in vitro, without the presence of host tissue. In one embodiment of the subject invention, Pasteuria endospores, such as those that infect the rootknot nematode Meloidogyne arenaria or other host nematodes, are grown in vitro under acidic conditions. The process of the subject invention is highly advantageous because Pasteuria can be grown in the absence of nematode tissue.